OT: 'best' dynamic language

[Manlio Perillo]

Igor Sysoev ha scritto:
> [...]
>>>>> It seems that Neko as well as Lua, perl, etc do the same in memory
>>>>> allocation failure case: exit() or nothing, i.e., segfault.
>>>>>
>>> >From what I can see, Lua (as Python) throws an exception in case of 
>>>> memory allocation failure.
>>>>
>>>> Python uses a statically allocated object for the Memory Error exception.
>>>>
>>>> Lua uses _longjmp/_setjmp, with integer representing error codes.
>>>> It only calls exit if no exception handler is installed.
>>> Well, but what can I do in exception handler ?
>>> Destroy a whole interpreter, leaving various leaks ?
>>>
>> With Lua you can supply you allocator function.
> 
> It does not resolve the problem. The interpreter internally 

The Lua interpreter?

> must test
> result of EVERY function that may fail on memory allocations:
> 
> void *
> interpreter_function0()
> {
>     p = interpreter_function1();
>     if (p == NULL) {
>         some rollback operations
>         return NULL;
>     }
> }
> 

Not sure to understand, but since memory allocation failure is signaled 
via an exception, the code flow is quite different.

 From http://www.lua.org/source/5.1/ldo.c.html#luaD_rawrunprotected:

   struct lua_longjmp lj;
   lj.status = 0;
   lj.previous = L->errorJmp;  /* chain new error handler */
   L->errorJmp = &lj;

   LUAI_TRY(L, &lj,
     (*f)(L, ud);
   );

   L->errorJmp = lj.previous;  /* restore old error handler */
   if (lj.status != 0) {
      ... if memory error, destroy the interpreter
   }


and:
#define LUAI_TRY(L,c,a) if (setjmp((c)->b) == 0) { a }






Manlio Perillo